+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: AGPL-3.0
- require 'faye/websocket'
+require 'rack'
+require 'faye/websocket'
+require 'eventmachine'
- class RackSocket
+# A Rack middleware to handle inbound websocket connection requests and hand
+# them over to the faye websocket library.
+class RackSocket
- DEFAULT_ENDPOINT = '/websocket'
+ DEFAULT_ENDPOINT = '/websocket'
- def initialize(app = nil, options = nil)
- @app = app if app.respond_to?(:call)
- @options = [app, options].grep(Hash).first || {}
- @endpoint = @options[:mount] || DEFAULT_ENDPOINT
- end
+ # Stop EventMachine on signal, this should give it a chance to to unwind any
+ # open connections.
+ def die_gracefully_on_signal
+ Signal.trap("INT") { EM.stop }
+ Signal.trap("TERM") { EM.stop }
+ end
- def call env
- request = Rack::Request.new(env)
- if request.path_info == @endpoint and Faye::WebSocket.websocket?(env)
- ws = Faye::WebSocket.new(env)
+ # Create a new RackSocket handler
+ # +app+ The next layer of the Rack stack.
+ #
+ # Accepts options:
+ # +:handler+ (Required) A class to handle new connections. #initialize will
+ # call handler.new to create the actual handler instance object. When a new
+ # websocket connection is established, #on_connect on the handler instance
+ # object will be called with the new connection.
+ #
+ # +:mount+ The HTTP request path that will be recognized for websocket
+ # connect requests, defaults to '/websocket'.
+ #
+ # +:websocket_only+ If true, the server will only handle websocket requests,
+ # and all other requests will result in an error. If false, unhandled
+ # non-websocket requests will be passed along on to 'app' in the usual Rack
+ # way.
+ def initialize(app = nil, options = nil)
+ @app = app if app.respond_to?(:call)
+ @options = [app, options].grep(Hash).first || {}
+ @endpoint = @options[:mount] || DEFAULT_ENDPOINT
+ @websocket_only = @options[:websocket_only] || false
- ws.on :message do |event|
- puts "got #{event.data}"
- ws.send(event.data)
+ # from https://gist.github.com/eatenbyagrue/1338545#file-eventmachine-rb
+ if defined?(PhusionPassenger)
+ PhusionPassenger.on_event(:starting_worker_process) do |forked|
+ # for passenger, we need to avoid orphaned threads
+ if forked && EM.reactor_running?
+ EM.stop
end
-
- ws.on :close do |event|
- p [:close, event.code, event.reason]
- ws = nil
+ Thread.new do
+ begin
+ EM.run
+ ensure
+ ActiveRecord::Base.connection.close
+ end
+ end
+ die_gracefully_on_signal
+ end
+ else
+ # faciliates debugging
+ Thread.abort_on_exception = true
+ # just spawn a thread and start it up
+ Thread.new do
+ begin
+ EM.run
+ ensure
+ ActiveRecord::Base.connection.close
end
-
- # Return async Rack response
- ws.rack_response
- else
- @app.call env
end
end
+ # Create actual handler instance object from handler class.
+ @handler = @options[:handler].new
end
+ # Handle websocket connection request, or pass on to the next middleware
+ # supplied in +app+ initialize (unless +:websocket_only+ option is true, in
+ # which case return an error response.)
+ # +env+ the Rack environment with information about the request.
+ def call env
+ request = Rack::Request.new(env)
+ if request.path_info == @endpoint and Faye::WebSocket.websocket?(env)
+ if @handler.overloaded?
+ return [503, {"Content-Type" => "text/plain"}, ["Too many connections, try again later."]]
+ end
+
+ ws = Faye::WebSocket.new(env, nil, :ping => 30)
+
+ # Notify handler about new connection
+ @handler.on_connect ws
+
+ # Return async Rack response
+ ws.rack_response
+ elsif not @websocket_only
+ @app.call env
+ else
+ [406, {"Content-Type" => "text/plain"}, ["Only websocket connections are permitted on this port."]]
+ end
+ end
+end
projects / arvados.git / blobdiff